The development of school-based obesity screening has been recommended by many public health groups but little is known about the effectiveness of this policy-based obesity prevention strategy. The proposed research will utilize a naturalistic, longitudinal design to study the effectiveness of different BMI screening practices and different feedback/education approaches on preventing obesity among elementary age children. The project capitalizes on an existing infrastructure for BMI tracking and obesity prevention within the state of Pennsylvania. Pennsylvania is one of four states that provide BMI screening results to parents of all K-12 students annually. The Pennsylvania Advocates for Nutrition and Activity (PANA), administered by Pennsylvania State University (PSU) has partnered with the Pennsylvania Department of Health (PDH) to coordinate training, parent communication and education efforts. This infrastructure will make it possible to evaluate the effectiveness of different BMI screening approaches as well as to evaluate the additive benefits of supplemental behaviorally-based screening and family-based education for the prevention of overweight and obesity. The goal of Aim 1 is to evaluate the impact of different BMI reporting practices on school-level BMI outcomes. Longitudinal (3 year) trends in BMI will be related to the type of BMI reporting to determine the relative effectiveness of different approaches. The goal of Aim 2 is to evaluate the potential of employing a validated, behaviorally-based screening tool (Family Nutrition and Physical Activity Screening Tool) in conjunction with standard BMI reports to promote awareness and changes in home environments. Schools will be randomized to receive the standard or supplemental report and effects will be evaluated with surveys and BMI trends. The goal of Aim 3 is to evaluate the effectiveness of an Extension-based family education program (Family Fitness) when implemented as an extension of normal BMI screening programming. The proposed initiative takes advantage of the natural experiment taking place within the state of Pennsylvania to answer important questions about how to enhance the effectiveness of BMI screening, a widely recommended public health strategy. The long-term goal is to develop an evidence-base to facilitate the adoption of primary prevention strategies to reduce risks for overweight and obesity before body changes and behaviors have become entrenched.